The present invention relates to a control member of the capacitive type for controlling at least one functional member in particular of a motor vehicle, and it also relates to a piece of vehicle equipment including such a member.
Pieces of motor vehicle equipment are incorporating ever increasing numbers of control members for controlling functional members of vehicles.
Several pieces of equipment placed in the passenger compartment of a vehicle receive control members of this type, which are then made available to users of the vehicle.
By way of example, these pieces of equipment can be formed by door panels, the dashboard, or indeed a central console of the vehicle.
In general, control members are grouped together in control panels carrying various members, such as, for example, switches, pushbuttons, or indeed rotary knobs included in electrical circuits for controlling functional members.
However, it will be understood that such members present various drawbacks, in particular in terms of the space they occupy and their reliability, particularly since they make use of moving parts.
Another problem associated with using members of this type lies in the complexity of mounting and installing them on board a vehicle, requiring the use of fasteners (screws, panels, and the like) and assembly time that is relatively lengthy.
Touch-sensitive detectors are known in general terms from elsewhere.
Reference can be made for example to the following documents: FR-A-2 779 889, FR-A-2 737 359, U.S. Pat. Nos. 4,022,296, 5,572,205, and 5,270,710.
Those detectors operate on the principle of detecting a change in capacitance by means of an electrode placed, for example, on a printed circuit board beneath a control operating zone, with such variation in capacitance being subsequently analyzed and processed by an electronic circuit enabling some arbitrary function to be controlled.
Such detectors have the advantage of not presenting any moving parts, but they suffer from the drawback of no feedback to the user, and in particular no tactile feedback.
Thus, for example, with a touch-sensitive system of the kind described in document U.S. Pat. No. 5,572,205, where provision is made for a rigid support with a capacitive sensor on one face of the support and an operating zone in register therewith on the other face of the support, the user perceives no sensation of pressing a button.
That can be a drawback, particularly if the user is the driver of the vehicle and is pressing on the control members without looking at them.
Having no tactile feedback, the user can end up pressing several times on the operation zone, thereby running the risk of not obtaining the desired response.
In addition, that also raises problems with concentration on driving the vehicle.
Document U.S. Pat. No. 4,022,296 describes a control unit having capacitive control switches which likewise raises such problems.
The object of the invention is thus to resolve these problems.
To this end, the invention provides a control member of the capacitive type for controlling at least one functional member in particular of a motor vehicle, the control member comprising a rigid support structure, at least one capacitive touch-sensitive detection cell located on or close to one of the faces of said support structure, and at least one control operating zone located on or close to the other face of said support structure in register with said capacitive touch-sensitive detection cell, wherein the control operating zone includes elastically deformable means.
According to other characteristics:
the elastically deformable means are independent of controlling the functional member;
the elastically deformable means have a rest position in which the finger of an operator in contact with the operating zone lines outside the touch detection volume, and a deformed position in which the finger of the operator in contact with the operating zone lies within the touch detection volume;
the elastically deformable means are formed by a projecting portion of an intermediate piece of elastically deformable material fixed beneath the support structure;
the rigid support structure carries a printed circuit board having the capacitive cell and a light source fixed thereon;
the intermediate piece carries a printed circuit board having the capacitive cell and a light source fixed thereon;
a mask representing a pictogram associated with the function controlled by the member is associated with the intermediate piece or with the printed circuit board;
the control operating zone is marked by a portion in relief of the support structure; and
the intermediate piece and the printed circuit board are of translucent material, and the light source is fixed beneath the printed circuit board.
According to another aspect, the invention also provides a piece of motor vehicle equipment fitted with at least one functional member control member as defined above.
According to other characteristics:
it comprises a support structure having a flexible and translucent covering skin placed thereon, and the support structure includes at least on opening beneath which there are placed means constituting a touch-sensitive detector and a light source;
the means forming a touch-sensitive detector are carried by a translucent printed circuit board with the light source fixed beneath it;
the covering skin carries a mask representing a pictogram associated with the function controlled by the member;
the printed circuit carries a mask representing a pictogram associated with the function controlled by the member;
the opening in the support structure is of a shape representing a pictogram associated with the function controlled by the member;
the opening in the support structure is formed in a portion in relief of said structure; and
the means forming a touch-sensitive detector are connected to electronic analyzer means for controlling the functional member and for controlling the power of the light source.